HIGH BLOOD PRESSURE | Controversy
Caution: the American College of Cardiology and the American Heart Association jointly issued new guidelines on November 13, 2017 for treating high blood pressure that may be hazardous to your health. Startling media coverage of these new guidelines regarding diagnosis and treatment fails to acknowledge the significant disagreement that exists regarding the basic tenets of the condition. Even among the most highly respected professional societies, no uniform definition exists of what precisely constitutes high blood pressure (HBP). Of course
in the absence of agreement on a diagnosis, it seems highly disingenuous to recommend lifelong therapy.
Everyone agrees that excessive blood pressure wreaks havoc on the vascular system over a period of years to decades. Along with cigarette smoking, obesity and improper diet, HBP ranks among the leading causes of preventable premature death both in the United States and throughout the worl
d. Complications of untreated HBP include heart attack, stroke, end stage renal disease, heart failure, cardiovascular related death and most
likely a tendency to develop dementia.
BLOOD PRESSURE BEFORE MODERNIZATION AND AGE
In primitive societies isolated from western influences blood pressure remains normal throughout life. Unfortunately dietary indiscretions, excessive salt, obesity and physical inactivity combine to progressively elevate blood pressure to unhealthy levels in at least 1 in 3 American adults with the incidence in African-Americans exceeding 40%. While relatively few teenagers develop HBP, the incidence rises to over 65% among senior citizens.
Until now most organizations accepted a systolic blood pressure reading up to and including 120 mm as normal and suggested intervening only when it exceeded 140 mm. Against this background, the American College of Cardiology and the American Heart Association unilaterally decided to redefine elevated blood pressure as systolic readings between 120-129 mm while labeling measurements at or above 130 mm as hypertension worthy of some treatment.
In effect this expands the number of people with HBP to about half of those in their fifties and 80% of individuals over age 65 or so. By their calculations more than 100 million adults fit into their definition of a medical disease with millions of additional people requiring daily treatment to minimize their risk of unwanted cardiovascular disease.
Fortunately other organizations appear more restrained in their recommendations. In January, 2017 the American College of Physicians together with the American Academy of Family Practice noted that “The evidence showed that any additional benefit from aggressive blood pressure control is small…” They continue to recommend commencing blood pressure lowering therapy when the systolic level exceeds 150 mm among healthy individuals beyond age 60. In the presence of known vascular disease, diabetes, kidney dysfunction or abdominal obesity they suggest beginning treatment when the systolic pressure exceeds 140 mm.
The United States Preventive Services Task Force agrees with these guidelines from just described.
OUTSIDE THE UNITED STATES
Recommendations from our northern neighbors, Hypertension Canada in 2017 actually accepts a systolic level of 160 mm as their trigger point to initiate therapy in the absence of microvascular target organ damage or the presence of any traditional risk factor cardiovascular disease. They allow initiation of treatment at a systolic level of 140 mm in the presence of macrovascular target organ damage or other risk factors but acknowledge a lack of evidence from randomized controlled studies to support this lower limit.
The International Society of Hypertension maintains the traditional 140 mm guidance and notes a lack of evidence to support previous recommendations of others to begin therapy with levels in excess of 130 mm even in the presence of diabetes, chronic kidney disease or coronary artery disease.
In England their National Institute for Heath a
nd Care Excellence or NICE position remains that everyone with a systolic pressure beyond 160 mm should receive treatment. Additionally they lower the treatment threshold to 140 mm in the presence of target organ damage, established cardiovascular disease, kidney issues, diabetes or a calculated 10 year risk of cardiovascular disease greater than 20% as obtained with an internet calculator.
The European Society of Cardiology, the equivalent of our American College of Cardiology and American Heart Association, reaffirmed their guidelines in June, 2017. For people over age 60, they recommend lowering systolic levels from in excess of 160 mm to between 150-140 mm except in the presence of diabetes where a level of less than 140 mm is preferred. For those younger than age 60, they also suggest maintaining the lower number.
Obviously significant differences exist regarding what systolic blood pressure reading should trigger therapy with opinion often superseding properly designed and completed randomized controlled studies. In spite of this, all medical societies and professional organizations express the necessity of lifestyle modification as a cornerstone of controlling HBP. Without proper attention to this linchpin, no oral anti-hypertension regimen will achieve its desired level of success.
Busy medical practitioners as well as non-professionals routinely fail to appreciate the importance of lifestyle modification in controlling blood pressure. Proper attention to these factors actually may be rewarded with such significant improvement in systolic levels that anticipated medical therapy may no longer be required. Simply taking a pill rarely suffices to provide the appropriate degree of risk reduction. Eliminating dietary indiscretions, consuming adequate quantities of fruits, vegetables and nuts, avoiding excess sodium, controlling body weight and exercising appropriately provide benefits equivalent to daily blood pressure medication.
WHAT’S THE EVIDENCE FOR A CHANGE IN POLICY
So with all of this in mind, why did the American College of Cardiology and the American Heart Association feel pressured to publish new guidelines at this time? Was it to combat an increasing incidence of death from heart disease? No, actually the toll of fatal cardiovascular events has steadily fallen with the current yearly number of fatalities more than 50% below the level of 50 years ago.
The major impetus for the change appear to stem from a study published in the New England Journal of Medicine in November 2015. Known as SPRINT, it evaluated the merits of reducing blood pressure in older hypertensive adults to less than either 120 mm or 140 mm. At entry, even though alrea
dy on two daily anti-hypertension medicines, the systolic blood pressure averaged 140 mm.
Another entry criterion required the presence of an underlying risk factor that increased the likelihood of cardiovascular disease. Examples include a previous heart attack, a stent, reduced kidney function, coronary artery calcification, an enlarged left pumping chamber or being in excess of age 75. The calculated probability of an untoward cardiovascular event within 10 years averaged more than 20% with the level in some individuals reaching nearly 40%. (online cardiac risk calculator). In spite of these predisposing factors 1 in 7 still smoked cigarettes with another 40% previously discontinued their habit. Basically everyone fit into the overweight category with a rate of obesity approximating 50%.
The standard therapy group received an average of about 2 pills a day and achieved a final blood pressure reading of 136 mm. Those in the intensive group averaged about 3 pills a day with 1 in 4 requiring 4 or more pills to arrive at a final blood pressure slightly above the targeted level of 120 mm. Unfortunately SPRINT lacked funding provisions for emphasis and guidance on lifestyle changes; as a result these were not emphasized.
A SHORTER SPRINT THAN ANTICIPATED
Although the original design of SPRINT included 5 years of treatment, the safety monitoring board terminated the study after a little more than 3 years. A dramatic difference appeared in the predetermined end points in favor of intensive therapy. According to the safety group the primary goal demonstrated a 25% relative reduction in the combined outcome of heart attack, acute coronary syndromes – basically unstable heart related chest pain, stroke, heart failure and death from any cardiovascular disease.
SPRINT TO REALITY
While a 25% relative reduction certainly sounds impressive, this number represents the difference between the absolute incidence in the intensive therapy group of 5.2% and the rate of 6.8% in the standard therapy group. In other word the relative decrease of 25% actually translates into an absolute difference of 1.6% or fewer than 2 people in one hundred. This hardly represents what most people imagine when they consider a 25% reduction in risk.
More importantly however when the rates for some of the individual components of the composite risk were evaluated separately, the results fail to impress. The likelihood of a heart attack was not significantly different in either group, neither was the incidence of stroke or unstable chest pain. Fewer cases of heart failure occurred but the actual difference in favor of intensive treatment was only 2/3 of 1%. Small changes favored the intensive therapy group with regard to cardiovascular mortality (relative reduction 43%, absolute reduction again only 2/3 of 1%). Unfortunately since the study was discontinued prematurely it will never be known whether these changes would continue or revert back to the mean, a form of statistical bias.
Other peculiarities include no statistically significant benefit for those with pre-existing kidney disease, women, African-Americans, people with previous cardiovascular disease and those with systolic blood pressure greater than 132 mm. Seniors older than age 75 improved but among those below this age the outcome was of only borderline significance.
SPRINT TO SIDE EFFECTS
As expected, side effects appeared considerably more frequent in the intensive therapy group. Blood pressure was too low often to a point of dizziness on standing that necessitated trips to the emergency room. Other problems resulting in hospital visits include fainting, blood chemical abnormalities and acute kidney damage. Among those receiving the intensive therapy some suffered a 30% decline in kidney function.
So were the initial monthly visits graduating into returns every 3 months worthwhile especially when coupled with the need for 3, 4 or more pills everyday? In the New England Journal of Medicine diagrams of the primary outcome and death from any cause appear almost identical unless greatly magnified. The calculated cost to achieve one quality adjusted life year approximates $50,000 more with the intensive therapy than the more traditional approach. Actually a previous trial calculated $650,000 per year of life gained with optimization of the diastolic blood pressure to less than 80mm.
Even the expert analysis from the American College of Cardiology published right after SPRINT became public seemed unenthusiastic about reducing the systolic blood pressure to less than 120mm. Special caution was urged for those elderly individuals with a history of falls or dizziness especially on arising from a bed or seat. Risk for problems rises significantly for frail individuals, those with hardened arteries and a diastolic blood pressure less than 60 mm.
AN ALTERNATIVE EXPLANATION
An unanswered but intriguing question involves the real but barely noticeable change in all cause and heart related mortality with SPRINT. While some may argue the lower blood pressure by itself provides sufficient explanation, an alternative theory may exist. More patients in the intensive group received chlorthalidone, a much longer acting diuretic than its more customarily prescribed relative hydrochlorothiazide. While early investigations many decades ago demonstrated significant cardiovascular benefits with chlorthalidone, for some inexplicable reason prescriptions for this long lasting drug dramatically declined. It provides nighttime coverage usually lacking with its more popular replacement. More reliance on the ACE inhibitor lisinopril may also explain some of the benefits.
Interestingly some experts in cardiology now suggest the merits of blood pressure lowering medicines for individuals without any evidence of HBP. It’s almost as if they view life itself as a heart hazard that must be combated with a pill of some variety.
HOW TO OBTAIN A CORRECT BLOOD PRESSURE READING
A final comment relates to the most mundane and rudimentary issue involved in the blood pressure arena: obtaining a reliable reading. Almost everyone visiting a healthcare provider experiences anxiety about what will transpire, aggravation during the often protracted wait and general unease regarding being able to be on time for the day’s next activity. All of these tend to raise the blood pressure.
A proper protocol exists for measuring blood pressure which requires a person be comfortably seated for at least 5 minutes in an examination room with a comfortable temperature. The arm must rest on a table at the same level as the heart and the cuff itself needs to be placed on the skin or over a loosely fitted garment. Additionally the cuff size must be appropriate for the individual’s arm circumference. In today’s society with greater level of obesity, this typically demands a large sized cuff; a standard sized cuff will provide incorrectly elevated measurements.
The blood pressure must be taken at least twice on a minimum of two separate appointments with an interval between individual measurements of at least 2 minutes. Exercise, caffeine, tobacco, meals and snacks must be avoided for a minimum of at least 15-30 minutes and preferably an hour prior to the readings. The urinary bladder should be empty.
Lack of attention to these details seems almost universal. Against this background the combined heart associations now propose labeling another 30 million Americans with the diagnosis of HBP.
A SIMPLE ALTERNATIVE
Permit me to make an observation. While most of us turn to prescription medicines as an answer to most of our ills, maybe a simpler, less expensive and healthier option exists. Over the past number of years beginning with the Lyon Diet Heart Study published in 1994 and evolving through the more recent PREDIMED study, it became obvious that dietary modification provides benefits for the heart and brain while offering protection against certain cancers and assists in weight loss.
Although not precisely defined, the so-called Mediterranean Diet encompasses a plentiful intake of fruits, nuts and vegetables while substituting fish and poultry for most red and processed meats. It urges drastic limitation of sugary foods but allows alcohol in moderation, especially wine, consumed at mealtimes. It urges considerable reduction in salt / sodium intake and encourages olive oil and alpha linolenic fats. Combine this with sufficient exercise and receive superb protection against the appearance or recurrence of cardiovascular disease while minimizing the need for medication along with its attendant costs and potential for adverse reactions.
Rather than taking the average of 5-7 pills that now seems customary among those over age 60, or even a greater number if we adhere to the new American College of Cardiology / American Heart Association recommendations, maybe now might be an appropriate time for reconsideration. If indeed the Mediterranean Diet offers such dramatic health benefits for the heart and beyond without the potential for troublesome side effects and merely require we break the sugar, salt and fat laden diet typical of western civilizations, does any rational alternative exist? Consider whether a Big Mac, Coca-Cola, Honey Nut Cheerios and french fries are really worth the almost guaranteed adverse health consequences that assuredly will follow in the form of HBP, premature heart disease, stroke, kidney disease, dementia and more?